Multicast, unidirectional link, combination of multiple communication links, multicast proxy, and multicast router are concepts or components which are widely used in multicast streaming sessions. Within a multicast streaming session, a multicast traffic is sent as a data stream to various receivers. The group of receivers however may vary in time. Receivers indicate their desire to receive a given multicast session using the IGMP protocol (RFC 3376).
A unidirectional link is a transmission channel that does not offer a return path. Multicast routing protocols exist that route multicast traffic through the Internet. For example, DVMRP (RFC 1075) and PIM protocols can be applied. There is also a daemon called IGMP-Proxy that proxies IGMP requests from one network to another network and thus implements a kind of IGMP snooping similar to what is described in RFC 454.
Smart management of the delivery network for multicast and broadcast traffic in a client device, such as a gateway can be done by selecting the most appropriate network adapter.
Multicast IP is composed with two main features. Firstly, an addressing scheme based on the group address wherein the IP address identifies a multicast group that is a TV channel/stream when applied to IPTV and secondly a IP signaling companion protocol called IGMP (IP Group Management Protocol) that is used by a terminal/application to signal its connection and disconnection to a group which is for example a TV channel. The IGMP protocol allows an IP network which is composed of one or more routers to optimize the distribution of multicast IP traffic by forwarding multicast IP packet only over branches where at least one group member has been signaled. Broadcast network has evolved in a way that it can transport IP streams including multicast IP streams. Alternatively, in the context of IPTV, IGMP is also used for selecting a TV channel.
Various attempts have been made in order to improve multicast transmission to a client in order to optimize distribution of the multimedia content.
In CN 101521626 A, a method for stepping control of a multicast program is shown which includes the following steps. Sending a multicast program request message to the access device by the terminal device; referring and obtaining the program step parameter by an access device according to said multicast program request message; and generating the multicast program data by the access device according to said program step parameter. The manufacturer can therefore order some multicast programs according to the multicast program stepping control terminal device in priority and provides a differentiated service according to the program.
In US 2006/0098618 A1, a method, a bridging device, a network of devices as well as a computer program product and a computer program element are shown which can be used for prioritizing transportation of isochronous data streams from a first bus having a first bandwidth to a second bus using a medium having a second medium bandwidth lower than the first bandwidth. The bridging device monitors control traffic relating to data streams originating from devices connected to the buses, polls the registers made available by the devices connected to the buses, prioritizes streams for transfer based on relevant information transported in the bus control traffic and/or made available by the devices connected to a bus and transfers streams over the medium based on the prioritizing. Accordingly, prioritizing streams for transportation over a wireless bridge between two data buses that is transparent to devices connected to the buses is possible.
In US 2011/0058551 A1, a method for managing multicast traffic through a switch operating in the layer 2 of the OSI model, and routers and switches involved in the method are shown. In one implementation, a router sends to a switch a message containing identification of a specific equipment which has requested specific multicast traffic, and also containing a specification of the specific traffic, and when the switch receives data carrying multicast traffic, based on the destination and origin addresses of the data, and based on the identification of the specific equipment and of the specification of the specific multicast traffic that it has received in the message, the switch deduces if the data carry the specific traffic that has been requested by the specific equipment, and decides through which of its ports it transmits the data.
In U.S. Pat. No. 6,487,170 B1, a method and apparatus are provided for making admission decisions in a packet switched network, such as a Differentiated Services (DiffServ) Packet Network. According to one aspect, admission control decisions are based upon local information. An average premium service bandwidth utilized on an output link of a network device during a predetermined window of time is calculated. A determination regarding whether to accept or reject a request for a premium service flow involving the output link is made based upon the request, a total premium service bandwidth available on the output link, the average premium service bandwidth, and bandwidth request information associated with one or more flows that have been admitted within a predetermined holding time interval. According to another aspect, multicast flows are supported. A measure of utilized premium service bandwidth is calculated for each of the output links of a multicast-capable network device. A request for premium service bandwidth for a multicast session is forwarded onto those of the output links specified by a multicast routing protocol which have sufficient premium service bandwidth available to accommodate the request based upon the total premium service bandwidth available on the output link, the measure of utilized premium service bandwidth on the output link, and the request. For each of the output links associated with the multicast session, a link state is maintained. The link state indicates the current state of a state machine that determines the behavior of the multicast-capable network device for the corresponding output link of the multicast session. Multicast packets that are subsequently received are forwarded according to the link states associated with the output links.
The paper of Wan-Ki Park and Dae-Young Kim: “Convergence of Broadcasting and Communication in Home Network Using an EPON-Based Home Gateway and Overlay”, IEEE Transactions on Consumer Electronics, Vol. 51, no. 2, pages 485-493, 2005, describes home network systems including a home gateway which are expected to facilitate the convergence of broadcasting and communication services to complement the ubiquitous computing and services. A modified architecture is shown that integrates broadcasting and data services in a home network. For this architecture, an overlay transport mechanism in access network and IP multicast techniques of the Internet group management protocol (IGMP) and IGMP snooping in a home network is used.
Furthermore, it is known to select dynamically, in the head-end, the most appropriate network which is a broadcast unidirectional link like DVB-T, DVB-C or DVB-H or broadband link to deliver IP multicast traffic.
Such a concept has been described in EP 1298836 A1. Within this document, a principle is shown which attributes to privilege the broadcast link when a given number of users request the same content and save the broadband bandwidth.
This concept, however, presents some limitations. The multicast content available either over broadband or broadcast is selected by the operator. Consequently, the quantity and diversity of multicast contents concerned by this load balancing is limited. If the user wants to receive other multicast content, this last will be automatically delivered over broadband, even if it is much more queried than other multicast traffic delivered over broadcast. Furthermore, the client is seen as a simple terminal with a single broadcast adapter and receiving a single IP multicast service simultaneously. Optimizing can be done for the delivery of multiple IP multicast streams (and also broadcast ones) to the home network.
Accordingly, there is a need in the art to overcome, at least partially, the problems associated with the prior art systems.